1California National Primate Research Center, University of California at Davis, 2Department of Anthropology, Pennsylvania State University, 3Department of Population Health and Reproduction, School of Veterinary Medicine, University of California at Davis
Friday All day, Plaza Level
Among rhesus macaques, novel males establish their group membership and rank through a combination of social interactions with female and male residents. What is less well understood is the degree to which novel males establish their status through female grooming relationships versus male competition. We present our assessment of changes in male ranks and male survivorship in the group following the introduction of novel males into an established group of adult females in a large social group of rhesus macaques at the California National Primate Research Center (CNPRC). We evaluated the hypotheses that females prefer adult (>5 years of age) over sub-adult (4-5 years of age) males and female preference correlates with increased male rank and survivorship in the group. The diversity of female groomers was greater for novel adult compared to novel sub-adult males (x=1.23 groom diversity index versus x=0.16 groom diversity index; LR Χ2 =17.85; df=1; p<0.0001). The results of survival analysis demonstrate that adult males remained in the group longer than sub-adult males (x=154 days versus x=60 days; log-rank X2=10.72; df=1; p=0.0011). Additionally, sub-adult male ranks dropped dramatically and adult male ranks increase dramatically after the all-male group was introduced to the female group. These results combined with data presented by Seil et al (these proceedings) support female preference as a driving force in male rank relationships and longevity in social groups, while male competition is less influential in determining male success (measured by increased rank and greater survivorship) in the group.
This project was supported by National Institutes of Health grants #R24 RR024396 and #PR51 RR000169